In the past, aircraft were mostly or totally built up with metallic components, providing a good performance in terms of mechanical behavior but, as a drawback, they are penalized in terms of weight.
One of the most important solutions was the use of composite fiber reinforced polymers (CFRP) for major structural parts, achieving an important weight savings and cost operations decrease.
Composites have been demonstrated to fulfill the following requirements:
Weight savings.
Be cost effective.
Meet structural requisite under aircraft conditions.
Beneficial cost/weight relation.
A horizontal tail plane (HTP) is a structure comprising a center structural box section, called a torsion box and two outer sections, the forward section known as the leading edge and the rearward section known as the trailing edge.
Trailing edges are the transition between the torsion box and the control surfaces. Trailing edges usually comprise an upper cover and a lower cover, both formed by a set of panels.
These panels are sandwich type panels. Standard architecture also includes of a set of ribs extending between the upper cover and the lower cover. These ribs are of two kinds, bearing ribs and trailing edge ribs. Trailing edge ribs are optional and therefore a trailing edge without these ribs is possible. Bearing ribs hold the hinge line of the control surfaces while trailing edge ribs are used to provide stability to the trailing edge structure.
Upper panels are joined to the ribs by means of rivets while lower panels are joined by means of screws to a lower flange of the ribs, so the panels which make up the lower cover can be opened to gain access for maintenance tasks of elements such as systems, actuators or fittings.
A known method for manufacturing said elements uses prepreg technology. Each of the different components is manufactured separately, including lay-up, forming and curing processes. Afterwards they are assembled together and joined by means of rivets.
Drawbacks of the known structure are the weight of the rivets used to join the different components and the amount of time needed for the assembly process due to the fact that it includes not only providing a large number of elements but also the need to link these elements together.